There is a known composition to form an antireflective film used in a lithography process using an ArF excimer laser (wavelength: about 193 nm) as a light source (see Patent Document 1). Patent Document 1 discloses a composition containing acrylic resins which are copolymers and have a benzene ring, a lactone ring and a hydroxyalkyl group each independently in side chains of the copolymer.
Patent Document 2 discloses an antireflective film forming composition containing a reaction product between an isocyanuric acid compound having two or three 2,3-epoxypropyl groups and a benzoic acid compound. Further, Patent Document 3 discloses in Example 1 thereof, an antireflective film forming composition containing a reaction product between tris(2,3-epoxypropyl) isocyanurate and 4-hydroxybenzoic acid. However, in both of Patent Documents 2 and 3, there is not disclosed the use of 2,4-dihydroxy benzoic acid.
As for others, there is a known antireflective film forming composition containing 2,4-dihydroxy benzoic acid (see Patent Document 4). Patent Document 4 discloses in Example 5 thereof, a composition containing a reaction product obtained using as a compound having at least two glycidyl ether structures, polyglycerol polyglycidyl ether and as an aromatic compound, 2,4-dihydroxy benzoic acid and benzoic acid. However, there is not disclosed a linear polymer obtained by a condensation polymerization of a di-functional diglycidyl ester compound with 2,4-dihydroxy benzoic acid. When the multi-functional glycidyl ether as described above is used, the reaction product is mainly an oligomer and thus is difficult to develop into a high molecular weight and has low thermal stability, so that there is caused a problem that when a composition containing the reaction product is thermally cured, a large amount of sublimates is generated, which have been elucidated by the study of the inventors of the present invention.
Patent Document 1: International Publication No. WO 03/017002 pamphlet
Patent Document 2: Japanese Patent Application Publication No. JP-A-2005-321752
Patent Document 3: U.S. Patent Application Publication No. 2004/6110089 specification
Patent Document 4: Japanese Patent Application Publication No. JPA-2004-212907.